Here's an example: yesterday, DD 8, got all dressed up for carol service at local church, my mother was taking her. She wore her new velvet sequinned skirt, couldn't find a suitable top to go with it so borrowed one of mine, was all blinged up and sequinned and feeling fab. One minute she was dancing around looking forward to the carol service, next she came running up the stairs crying, saying she didn't want to go because Nanny had said she looked ridiculous and silly.
It upset her for about half an hour and just as she'd calmed down about it, once again my mother made some fucking stupid unnecesary remark which set her off again. She ended up changing outfits because my awful mother had made her feel so bad. And she'd felt beautiful an hour before. 
I didn't even feel angry about it because I'm so used to this sort of mindless cruelty from my mother. Cutting her out of my life isn't an option, making her stop is never going to happen, so what can I do to make sure that my DD develops the same immunity it took me 42 years to develop to this shit?